The present invention relates to plastic containers. In particular, the present invention relates to a plastic container having a tamper-proof and/or tamper-evident closure mechanism that protects against unauthorized opening of the container.
As incidents of product tampering have increased in recent years, the marketplace has demanded that food and pharmaceutical containers contain features that both inhibit unauthorized opening of the containers and provide clear evidence of tampering when unauthorized opening takes place. The problem of providing an effective closure system is particularly acute with wide-mouth plastic containers, for which it is desirable to provide ease of repeated opening and closing by the purchaser after the product is bought. Although a tamper-proof and tamperevident closure system will interfere to degree with the initial opening, it should not substantially impede subsequent openings.
One proposal for a tamper-proof closure system, based on U.S. Pat. No. 4,027,775, provides a container body with an outwardly extending flange disposed immediately beneath the lower edge of the container lid. The flange includes a removable section frangibly connected to the container body. The flange inhibits access of the human finger to the lower edge and thus makes opening the container difficult until the removable section is detached and a portion of the lid's lower edge is exposed. Unfortunately, this configuration does not significantly deter unauthorized opening of the container by prying between the flange and lower lid edge with, for example, a knife blade. In addition, it does not provide readily apparent visual evidence of unauthorized opening.
Another proposed system, disclosed in U.S. Pat. Nos. 4,024,976 and 4,190,175, provides an L-shaped tear strip frangibly attached to the container body side wall to cover the lower edge of the lid. Access of one's finger to the lower lid edge is barred until the tear strip is removed. Although this system provides visual evidence that the container has been opened in the conventional manner, it will neither prevent nor render visually evident tampering by someone who inserts a knife blade or similar tool through the weakened section between the strip and container body side wall to push off the lid.
The present invention is intended to provide a lo container closure system that both inhibits unauthorized opening to the container and leaves visual evidence when an attempt is made to open the container.
The present invention also is intended to provide a tamper-proof and tamper-evident container closure system that guards against unauthorized opening by use of a knife blade or similar tool.
Additional advantages of the present invention will be set forth in part in the description that follows, and in part will be obvious from that description or can be learned by practice of the invention. The advantages of the invention can be realized and obtained by the apparatus particularly pointed out in the appended claims.